DE10308328A1 - Process for producing an exposed substrate - Google Patents

Abstract

Method for producing an exposed substrate which has at least two different image areas. In this case, the substrate is provided with at least two photoresist layers which are adapted to the type of the image areas to be produced.

Description

The invention relates to a method for producing an exposed substrate which has at least two Has image areas.

To secure security documents such as banknotes, ID cards or the like, optically variable elements are often used, which are made up of diffraction gratings. Such elements are referred to below as grid images. These can be grating images in which the first and higher diffraction arrangement is used for viewing, such as, for example, holograms or those grating images which are composed of grating surfaces. As an alternative, grating images are also used in which the zeroth diffraction order is used, such as in US-A-4,892,385 and US-A-4,484,797 described.

The first-order grid pictures and the zero-order grid images differ essentially in that the lattice constant is greater than the light wavelength must be while in the latter the grating constant is preferably chosen to be smaller than the wavelength, in particular if you want to observe the pure zero order. While at First-order lattice images make the lattice constant crucial for color variability and the grid line structure plays a subordinate role, the reverse is true for the zero-order grid images.

The diffraction structures used as security elements are mostly used as embossed holograms manufactured. Therefor becomes a photoresist layer on a substrate with laser light or exposed to electron beams. Radiation-sensitive, film-forming materials, e.g. Photoresists, referred to, their solubility behavior changes due to exposure or radiation. One differentiates positively and negative working photoresists. The former are identified by photochemical Degradation or transformation of functional groups under radiation easily soluble, whereas the latter is difficult due to crosslinking or photopolymerization soluble until insoluble become.

After developing the photoresist layer arises a mountains and valleys showing structure, which are molded by electroplating can. The profile structure is preferred for first-order grid images sinusoidal, with zero-order grid images box-shaped or trapezoidal. The replicated structure can then be reproduced and used to manufacture dies be used.

Grid images are also known at which combine several exposure steps have to. Two methods are known for this.

In a first procedure Partial areas of a photoresist layer covered with masks and first the unmasked sections of the photoresist layer e.g. with laser light a first wavelength exposed to produce a diffraction structure. In further procedural steps the already exposed parts of the photoresist layer are covered and the parts of the image now freed from the masks e.g. with laser light other wavelengths exposed to produce further diffraction structures.

This method has the disadvantage that it cannot be applied if in a grid image different resist layer thicknesses are required, e.g. when assembling of zero-order grid images.

In another known method circumvented this problem by using multiple dies on galvanic Ways of independently exposed photoresist layers are produced. Any stamp contains only a part of the overall picture. To get the big picture become the dies coexisted in thermoplastic material. This method is disruptive however, that of side by side embossing occurring seams.

Based on this state of the art the invention has for its object to provide a method with which exposure to different types of radiation is easy is to be accomplished and, where appropriate, also the layer thickness can be adjusted in different areas of exposure.

This task is accomplished through a process with the characteristics of independent Expectations solved. In depend on it claims Advantageous refinements and developments of the invention are specified.

According to the inventive method for Production of a resist master that has at least two different ones Has image areas, at least two photoresist layers used, adapted to the type of image areas to be produced are. This has the advantage that each image area is under optimal Conditions can be established and thus optimal optical Effect shows.

The term "photoresist" means in the sense the invention a radiation-sensitive material, the chemical Properties, especially its solubility behavior, through Exposure to light or particle radiation changes.

Photoresist materials are called "positive resist" referred to by photochemical degradation or conversion of functional groups easily soluble become. This means, the exposed areas are removed during further processing, the unexposed areas However, games remain.

Photoresist materials are used as "negative resist" referred to that difficult through crosslinking or photopolymerization soluble until insoluble become. This means, the unexposed areas are removed during further processing, while the exposed areas remain.

The term "grid image" is not used on grid line images limited, but includes any design of diffraction structures. Only if this term is used in contrast to a real hologram the term is to be understood in the narrower sense.

“Substrate” means any carrier material on what photoresist layers for one Exposure process can be applied. Glass plates are often used for this used under certain circumstances colored black or coated. It can however, already electroplated nickel shims are used that are already provided with any grid image. A further layer of photoresist is applied to this and with a second grid image corresponding to the photoresist used exposed and processed. About that plastic or metal foils are also suitable as substrates, which are already provided with a grid image, preferably in the form of an embossing are.

As "Resistmaster" it will be after the Invented substrate referred to, the at least one has exposed and developed photoresist layer. The resist master can be electroplated in further process steps and so-called embossed shims be processed further.

According to a first embodiment of the invention for the production of a resist master that has at least two different ones Has image areas, such as a real hologram and a grid image, used at least two layers of photoresist attached to the respective radiation type to be used are optimally adapted. For a holographic Exposure is common Laser radiation used for the lattice generation, however, often Electron beam. With the aid of the invention, it is thus possible to achieve such different Manufacturing variants combined on a substrate become.

Another selection criterion for the photoresist layers The profile to be generated can be found in the different image areas the relief structure. Zero-order grid images need as much as possible steep flanks while for first-order grid images flat flank angles are preferred. In particular, sinusoidal profiles sought. With the method according to the invention can therefore also zero-order grids with any first-order grids can be combined on a substrate.

The method according to the invention makes it possible but also, the different image areas with different To provide zero-order grid images. With this kind of grid images the color variability arises solely by the destructive interference of those on the surfaces of the Photoresists reflected radiation. The main parameter is therefore the profile depth of the relief structure, with the profile depth only depends on the layer thickness of the photoresist. This can be very accurate can be set and is preferably in the range of about 50 up to 200 nm. Accordingly, the substrate can also have at least two photoresist layers be provided, which consist of the same photoresist material, but have different thickness.

The photoresist layers according to the invention can already be arranged on the carrier material before the first exposure step. They are preferably one above the other applied, if necessary with protective layers in between.

The top layer is for generation of a first image area, e.g. regarding a first Radiation type, the next Layer on the other hand for creating a second image area, e.g. with regard to the Layer thickness or another type of radiation etc. Between the Resist layers may be "stop layers" that ensure that the layers are only exposed to the right radiation.

In a preferred embodiment will be one for optical holographic exposure suitable positive resist layer over a for electron beam exposure suitable positive resist layer applied, which for optical Radiation is insensitive.

This layer sequence is first exposed optically in the desired areas, for example with a hologram. This exposure only works in the upper layer, not in the optically insensitive layer underneath. The other parts are optically exposed over the entire surface and additionally with a desired electron beam grid image, such as in DE 102 26115 or DE 102 26112 described, acted upon. The optical exposure leads to the deletion of the upper layer in these areas, while the electron beam exposure penetrates the upper layer and forms an image in the lower layer. After the resist development, the two image areas are side by side.

According to a further embodiment according to the invention the individual photoresist layers are only in a suitable Phase of the manufacturing process applied to the substrate and exposed with the corresponding grid image.

In this way, a first layer of photoresist can first be applied, exposed and developed on the substrate. The quality of this first photoresist layer is adapted to the type of radiation used in the exposure or its layer thickness is optimized for a specific imaging method. In a further process step, a second photoresist layer is applied to the substrate and the first photoresist layer remaining thereon, exposed again and developed. Since the second photoresist layer can be selected independently of the first photoresist layer, a material can be used for the second photoresist layer that is optimal for a second radiation type or in its layer thickness for a specific image is optimized. The method according to the invention therefore makes it possible to produce different image areas lying next to one another, which may be seamlessly adjacent to one another, all image areas having an optimal quality or layer thickness due to the use of several specially adapted photoresist materials.

In a preferred embodiment becomes a negative resist layer in a first process step applied to the substrate and the desired image areas exposed. The substrate is then developed, which is not exposed areas of the negative resist are removed from the substrate. In a further process step, a second negative resist layer applied to the substrate and second Image areas are exposed.

That already in the first stage of the procedure Areas exposed in the first negative resist layer are imaged no further exposed in the second process section. By developing the second resist layer will eventually be through the second Resist material spilled Areas of the first resist layer exposed again. As a result a substrate with two photoresist layers arranged next to one another is produced in the form of mountains and valleys, hereinafter referred to as "relief structure". The relief structures in the first and second photoresist layers are the same Height trained and go seamlessly depending on the design of the exposed pattern into each other.

In another preferred method in a first process step instead of a negative resist a positive resist layer is applied to the substrate and the desired Image areas in the desired Design exposed to suitable radiation. To in the previously unexposed areas the positive resist layer entirely need to remove in a subsequent step the exposed areas of the first positive resist layer covered with a mask and the previously unexposed areas be intensively exposed. When developing the positive resist the patterns exposed in the first step are exposed in the positive resist layer and the areas of the substrate post-exposed in the second step completely freed from the positive resist. This creates next to the first positive resist layer space for the application of further layers of photoresist. The first positive resist layer and the subsequent photoresist layers are on the same Height.

In the described exemplary embodiments can Of course further process steps can be provided, in which further photoresist layers applied and exposed accordingly. Also negative resist layers and Positive resist layers can be combined as desired.

Before applying one new photoresist layer can be applied a thin barrier layer be the one for that ensures that when loosening the new photoresist layer the underlying photoresist layer not damaged becomes. The barrier layer is preferably made of an inorganic Material that is not attacked during the development process. On the other hand, it may be necessary to remove the barrier layer, after it serves its purpose has to remove it again when performing subsequent procedural steps disturbs. This removal must be done without damage the resist layer possible his. Metal layers e.g. this condition. They are not attacked by resist developers, can, however, with acids, bases or remove etching solutions, which in turn do not attack the resist.

The barrier layer can also be more Perform functions. Is for exposure of one of the photoresist layers, for example Electron beam used, the barrier layer can be used as a conductive layer be designed to derive the electrons after the energy release. A chrome layer is preferably used here. With optical Exposure needed if necessary, an effectively light-absorbing layer behind the photoresist layer. This is the case, for example, if the substrate or the layers themselves under the optical photoresist not enough Swallow light.

Can be particularly advantageous the inventive method use in the manufacture of diffraction structures that serve as security features for value documents or used for product assurance. Because the method according to the invention allows it, a diffraction structure with at least two different ones Produce image areas using different exposure methods were generated. For example, the diffraction structure can Part be designed as a real hologram, while other sub-areas only are designed as a grid image, which is produced, for example, by means of electron beam lithography has been.

For exposing a real hologram is, for example, a He-Cd laser with a wavelength of 442 nm and a highly sensitive photoresist are well suited. At the Expose using the usual holography process receives you get a relief profile with flat flanks that is very good in embossing stamp can be implemented.

However, if you use the same positive resist, diffraction structures in the electron beam lithography process to generate so receives rectangular relief profiles, which are not suitable for embossing, because the embossing lacquer gets stuck in the relief profile. On the other hand, one who works with a soft gradation brings less sensitivity Negative resist with a correspondingly adjusted electron beam focus trapezoidal to sinusoidal Relief profiles in one stamping process can be used very well.

But pure grid images can also be used different techniques. Depending on what is to be manufactured It may be useful for design different image areas different manufacturing techniques or radiation types to use to ensure optimal image quality and brilliance to produce optically variable effect. Different layer thicknesses can also be used be advantageous in different areas (with first-order grid images) or necessary (for zero order grid images). Here can the inventive method also used with the process steps described above become. The individual photoresist layers only have to be in the desired one Layer thickness can be applied to the substrate.

According to a further embodiment the invention can also be used only one photoresist layer, which in at least one partial area with light radiation, e.g. Laser radiation and in at least one further sub-area Particle radiation, e.g. Electron beam, is exposed. This has the advantage that grid images using different recording techniques generated, can be produced on a substrate and this substrate as a whole is further processed into an embossing tool can be. The production of different embossing tools and the explained with it Problems are therefore eliminated.

The image areas according to the invention can also partially or completely overlay. in this connection a photoresist layer is preferably used, which at least partially first with one diffraction structure and then in same area with a second or more diffraction structures is exposed or described.

For the described method according to the invention preferably a neutral carrier material, such as a glass plate, used, on which the individual layers of photoresist applied and be exposed and developed there. The manufactured in this way The substrate, the so-called “resist master”, is then galvanized molded and reproduced by known methods to create an embossing tool, such as an embossing cylinder.

Alternatively, instead of the neutral one support material also a plastic or already provided with a grid image Metal foil or an electroplating shim can be used. The grid picture is preferably in the form of a relief structure. For the production this intermediate product becomes a neutral carrier material, e.g. a Glass plate, coated with a first layer of photoresist and with the corresponding grid image or parts thereof Laser or electron beam exposed. This resist master will galvanically molded. Subsequently becomes either the electroplating shim produced in this way or one Plastic or metal foil using a galvanic shim based on this manufactured embossing tool embossed with the grid image was coated with another layer of photoresist. This too Photoresist layer is with a grid image or parts of an overall grid image exposed or described by means of an electron beam. Depending on the type of the photoresist used may be necessary after development of the photoresist further measures to make sure that the first grid image in the desired Image areas are exposed.

For example, become a positive resist used, this resist layer remains on the entire surface Support material while the structuring is only in the exposed area. They don't exposed areas therefore be removed again. For example, you can use the exposed areas over Masks or using a so-called washing process with a Provide metallization. In the washing process, all unexposed areas with a preferably water-soluble ink printed and the backing material subsequently entire area metallized. When loosening the ink becomes the one above lying metallization also removed, only in the exposed Metallization remains in areas. This protects the exposed areas also during the subsequent dissolving process of the photoresist layer, which only in the unexposed areas, for example by means of Acetone is removed. In a last step you can finally the metallization are removed. This substrate also forms a resist master, which, as already described, processes further becomes.

Another alternative is on the already structured carrier material, i.e. the embossed film or the shim, an embossable Lacquer layer, e.g. apply a UV varnish layer or thermoplastic layer, in which with a second stamping tool the wished Embossed grid picture becomes. This substrate also forms a resist master which, as described, to an embossing tool is processed further. Of course, this process can be arbitrary be repeated often. The procedures described last have besides the optimal adaptability of the photoresist layers the great advantage of the type of grid image or the recording method, that an existing grid image is supplemented and / or by additional ones Information can be customized.

The last two described Procedures are available e.g. if, for a banknote series, an optical variable security element to be produced, which is in the background one for all Denominations identical grid image, such as a country symbol, shows, and in the foreground one for the respective denomination individual symbol, such as the denomination self.

By means of the embossing tools produced according to the invention, security elements can be produced which are used to secure documents of value, such as banknotes, checks, etc. white cards or the like can be used. Embossed diffraction structure elements are also frequently used in the area of product assurance.

With the aid of the method variants according to the invention can zero-order grids and first-order grids for the first time or with particle radiation and lattice images generated by optical exposure can be combined as required in a resist master.

The invention is illustrated below by way of example the attached Drawings explained. Show it:

1a - d successive process steps when using negative resist layers;

2a - f successive process steps when using positive resist layers;

3a - d a further embodiment with two negative resist layers of different layer thickness;

4 resist master according to the invention in supervision;

5 Template for holographic exposure;

6 Example of a mask;

7 holographic exposure with the original according 5 and mask according to 6

8a - f successive process steps of a process in which a positive resist is first exposed holographically in a first step and then a negative resist is exposed using an electron beam;

9a - e further embodiment of the method according to the invention with photoresist layers lying one above the other;

10 another embodiment;

11a - c a further embodiment of the invention with a photoresist layer made of positive resist;

12 Negative resist exposed according to the procedure 11a . 11b ;

13 - 15 different layer structures, which in the 11 shown methods can be used;

16 - 18 further embodiments of the method according to the invention.

In the 1a to 1d Process steps of the method according to the invention are shown, in which firstly a photoresist layer 1 on a substrate 2 is applied. With the substrate 2 For example, it can be a glass plate, which, if optical holographic exposure is to take place, is preferably colored black in order to avoid reflections. The application of the photoresist layer 1 happens for example by putting on the substrate 2 a drop of photoresist material is given, which is applied evenly over the substrate in a resist spinner, eg a centrifuge 2 is distributed away. After that, the photoresist layer 1 cured by heating.

The thickness of the resulting photoresist layer 1 depends on the drop size, the spin speed and spin time, the temperature, the vapor pressure and other parameters. If in the photoresist layer 1 If diffraction structures are to be introduced, the thickness of the photoresist layer lies 1 between 100 and 1000 nanometers.

The method according to the invention is explained below using the example of the production of holographically produced diffraction structures. For this, in the 1 shown example as a photoresist layer 1 a negative resist layer is used.

This negative resist layer 1 after curing with uniform coherent wave fields 3 exposed in the area of the negative resist layer 1 interfere and in the negative resist layer 1 an in 1a Interference pattern indicated by dashed lines 4 form. The negative resist material and the radiation used are optimally coordinated. The exposure with the wave fields 3 is carried out so that the interference pattern 4 only in the area of a first image area 5 is formed while a second image area 6 remains unexposed. This can be achieved, for example, by using masks. The outline of the image areas 5 and 6 are each in accordance with that through the image areas 5 and 6 shown motif selected.

When developing, the unexposed areas of the negative resist layer 1 solved. According to the interference pattern 4 shows the negative resist layer 1 now mountains 7 and valleys 8th on, which are evenly sinusoidal in the example shown. Depending on the image to be displayed, the relief structure can also be of any complexity. This is particularly the case with real holograms. In the area of the image area 6 becomes the negative resist layer by the development process 1 completely solved so that the substrate 1 is again uncoated in this area.

According to 1c then becomes a second negative resist layer 9 all over the substrate 2 applied so that it also the first negative resist layer 1 covers. This second negative resist material 9 is optimally adapted to the type of radiation used for exposure. As in 1c indicated, the second negative resist layer 9 in the image area 6 also with coherent wave fields 10 exposed, but whose wavelength, for example, from that for the exposure of the first negative resist 1 radiation used is different. Here, too, forms in the image area 6 an interference pattern 11 from which is indicated by dashed lines.

The substrate 2 will be developed again. The result is in 1d shown. Since it is a negative resist, the exposed areas of the negative resist layer remain during development 9 stand. In the by the wave fields 10 unexposed areas becomes the photoresist layer 9 away. In particular, the through the second photoresist layer 9 filled in parts of the first photoresist layer 1 uncovered again. The different image areas 5 . 6 are directly adjacent to each other in the example shown. Of course, they can also be arranged at a distance.

If there are other separate image areas besides those in the 1a to d displayed image areas 5 and 6 are to be trained in the procedural steps 1a to 1d corresponding areas of the substrate 2 released by non-exposure. In further process steps, the procedure is then as in the 1c and 1d shown.

The method can be carried out not only with negative resist layers, but also with positive resist layers. The 2a to 2f show the corresponding process steps of the method according to the invention, using positive resist layers.

In a first process step, as in 2a shown the substrate 2 with a positive resist layer 12 coated. In the area of the image area 5 thereupon becomes the positive resist layer 12 with coherent wave fields 13 applied. These wave fields 13 interfere in the positive resist layer 12 and form an in 2a Interference pattern drawn in dashed lines 14 out. The material of the positive resist layer 12 is the type of radiation of the wave fields 13 customized.

The exposed areas of the positive resist layer 12 are then covered with a mask, which is covered by a transparent film with light-tightly masked areas 15 is formed ( 2 B ). Previously unexposed areas of the positive resist layer 12 which in subsequent process steps for further image areas 6 are provided using radiation 16 according to 2 B intensively overexposed.

After developing the substrate 2 and removing the exposed areas results in the in 2c Relief structure of the positive resist layer shown 12 , The positive resist layer 12 now shows a pattern of interference 14 corresponding relief profile with mountains 17 and valleys 18 on, which is also shown here only for reasons of clarity as a sinusoidal relief structure. Around the image area 6 with a diffraction structure is applied to the substrate 2 a second positive resist layer 19 applied. The second positive resist layer 19 is with wave fields 20 acted upon in the image area 6 in the positive resist layer 19 an in 2d Interference pattern drawn in dashed lines 21 form. The material of the positive resist layer 19 is due to the radiation type of the wave fields 20 customized.

In another, in 2e Process step shown are those with the wave fields 20 exposed areas of the positive resist layer 19 again with a mask 22 covered and the image area 5 as well as any other image areas not shown, intensively over the entire area with radiation 23 applied.

Finally, the substrate 2 developed and the exposed areas removed, so that on the substrate 2 in the 2f shown relief structures result.

With the here based on the 1a to 1d such as 2a to 2f The methods described are obtained in each case next to one another at the same height, ie photoresist layers lying directly on the substrate 1 . 9 . 12 . 19 , the material for the photoresist layers being selected in each case with regard to the radiation used for exposure, so that optimal results are achieved.

It should be noted that the positive and negative resist layers can also be combined with one another. For example, the process steps can be according to 1a and 1d the in the 2d to 2f Connect further process steps shown.

In certain embodiments it may make sense to apply a new layer of photoresist one thin each Barrier or auxiliary layer, e.g. made of metal, an oxide or the like, to bring up that for that ensures that when loosening the new photoresist layer the underlying photoresist layer not damaged becomes. The barrier layer is preferably made of inorganic material, which is not attacked in the development process.

The auxiliary layer can also be more Perform functions. Is for exposing one of the photoresist layers to an electron beam used, it is preferably formed as a conductive layer to to derive the electrons after the release of energy. In this case the barrier layer is preferably a chrome layer. At a Interference exposure, however, can be a highly absorbent thin layer be trained.

The invention is also not based on Limited process, in which the exposure by means of light radiation and particle radiation be combined. It can e.g. different wavelengths are also used for the exposures become.

Any types of grid images, how first-order and zero-order grid images are combined become.

The 3a to 3d show an embodiment of the invention in which the substrate is provided with two different image areas, which are characterized by different profile depth. This is the case, for example, with zero-order grating images which show different optical effects. In a first step, as in 3a shown a glass plate 60 with a first negative resist layer 61 Mistake. Since the profile depth depends solely on the resist layer thickness, the Re sis layer thickness can be set exactly. In the example shown, the resist layer thickness can be d ₁₂₀₀ nm. If for exposure to radiation 62 An electron beam can be used on the glass plate 60 be sputtered with a chrome layer before applying the negative resist layer. The thickness of this layer is approximately 20 nm. The negative resist layer 61 will eventually with the radiation 62 exposed such that trapezoidal exposed areas 63 arise.

The negative resist 61 is then developed, whereby the unexposed areas are removed and only the exposed areas 63 on the glass plate 60 remain as in 3b shown. Then a second negative resist layer 64 on the glass plate 60 applied. The layer thickness d _{2 of} this second negative resist layer 64 is 150 nm. This layer is finally exposed to the same radiation 62 , preferably exposed to an electron beam. The exposure takes place in the areas 63 neighboring areas 65 instead of. This negative resist too 64 is then developed, whereby the unexposed areas are removed so that only the exposed areas 63 and 65 on the glass plate 60 remain. The areas 63 . 65 are characterized by different profile depths d ₁ , d ₂ , which leads to different optical effects, especially with zero-order diffraction gratings.

Of course, this procedure can also using positive resist layers or a mixture made from positive and negative resist layers, as already explained with reference to the previous Fig. It is the same possible, any first-order grid image in one of the image areas to arrange.

4 schematically shows a resist master according to the invention 110 for an embossed hologram that has a first image area 100 has, which is exposed to light radiation, and a second image area 101 exposed to particle radiation. In the example shown, the optically exposed image area 100 a real hologram that represents a field of letters arranged in the background. The image area created with particle radiation 101 is formed by a letter "A" which appears to pulsate when the image is tilted and which is produced by means of electron beam lithography. The motifs can of course be chosen arbitrarily. The different image areas can also be nested in one another as desired.

The letter field generated holographically, ie by superimposing coherent light radiation 100 is in the area 101 interrupted or has a gap there 101 on. In this gap 101 is a letter "A" generated with particle radiation, in particular electron beam, which is composed of different band-shaped lattice structures, which is shown schematically by the different hatching.

Various process variants are described below with which such a resist master according to the invention is used 110 can be manufactured.

According to a first method, a template is used to produce the holographic background 102 used as in 5 is shown. This template 102 is optically exposed in a photoresist layer, using a mask 103 in the form of a letter "A" is used. The mask 103 is in 6 shown schematically. The mask 103 prevents holographic exposure of the photoresist layer in the area 101 and only the background is with the letter box 100 exposed. this shows 7 , In the recessed, unexposed area 101 is then the electron beam in 4 grating structure shown inscribed. The order of the exposure steps can of course be interchanged. As will be explained in more detail below, this resist master can be used for the production 110 one or more layers of photoresist can be used.

A first embodiment, in which two layers of photoresist are used, is shown in FIG 8a to 8f explained in more detail. Here's one as a substrate 2 serving black colored glass plate with a positive resist layer 24 made of the positive resist material A-RP 3040 with a layer thickness of about 0.50 micrometers. The positive resist layer is applied in a customary holographic apparatus with, for example, He-Cd laser 24 in the background 25 exposed in the usual rainbow hologram H1 / H2 process, while for the foreground 26 , ie the areas provided for the electron beam grid image remain unexposed. In 8a is this equipment only by laser radiation 27 indicated. It is also pointed out that, for reasons of clarity, only a small partial section of the substrate is shown.

According to 8b is now a mask, such as in 6 shown in contact with the substrate 2 brought. The mask is a transparent film 29 with light-proof masked areas 15 which are for the background 25 covers intended parts of the image and those for the foreground 26 intended areas. The substrate 2 is now using homogeneous UV light 30 nachbelichtet.

After developing the substrate 2 in the developer AR 300-35, this results in 8c schematically shown relief profile 24 , Below is a 30 nanometer thick chrome layer 31 , as in 8d shown, evaporated. On the chrome layer 31 will be accordingly 8e a negative resist layer 32 made of the negative resist material X AR-N 7720/25 with a thickness of 300 nm. In the designated area 26 the foreground becomes a grid image 101 with electron beam lithography, as in 8e shown, ge wrote. This is an electron beam 33 guided along the intended grid lines. The electron beam 33 as it were, writes the grid lines in the negative resist layer 32 on. The fully exposed substrate 2 is developed in the developer AR 300-48. This results in 8f shown relief profile 32 ,

9 shows an example in which the layers are not applied alternately with the work steps, but in which all layers are already available at the beginning of the process and the exposures can be carried out in succession without further coating processes.

On a glass plate 40 , preferably a polished quartz glass plate becomes a chrome layer 41 applied. A dark-colored positive resist is largely insensitive to optical radiation 42 applied, which is suitable for exposure to an electron beam and has a desired layer thickness for the electron beam exposure of, for example, 200 nm.

A 400 nm thick layer of positive resist is applied on top 43 applied, which has a good sensitivity for light radiation, for example for light from an He-Cd laser with a wavelength of 442 nm. The plate is now ready for exposure ( 9a ).

The order of the exposure steps now required is arbitrary. In the example shown, the optical exposure is started. The area intended for this 431 with a He-Cd laser 44 holographically exposed. The area so exposed 431 now contains the latent holographic image, which in the 9b is indicated by a dashed sine curve.

The photoresist area below 421 is not damaged due to its optical insensitivity and serves as an absorption layer due to its dark coloring in order to avoid unwanted light reflections. The area optically exposed in this way 431 is now through a mask 45 covered and the area intended for electron beam exposure initially with blue light over the entire surface 46 pre-exposed to the top photoresist layer in the area 432 to make solvable. The exposure to blue light 46 has because of the light insensitivity of the photoresist layer 42 no effect on the underlying photoresist layer area 422 ( 9c ). Then the electron beam exposure takes place 47 in this area ( 9d ).

The electron beam penetrates the upper layer of photoresist 43 and exposes the underlying electron beam resist layer 42 with the desired grid image. The damage caused by the electron beam in the top photoresist layer 43 are irrelevant since this layer is ultimately removed in this area. This completes the exposure.

During development, mountain and valley profiles now emerge from the latent images ( 9e ) as determined by the exposure. The area 431 shows a holographic image, the area 421 is undamaged because it was not exposed. The area 432 is removed because it was fully exposed and in the area 422 there is an electron beam grid image.

10 shows an alternative structure that is treated exactly like 9 , The difference is that instead of the chrome layer 41 a conductive polymer layer 51 is applied and a black colored glass substrate 50 is used. This structure brings about an even better suppression of reflections than the structure for the optical exposure 9 ,

This in 4 shown and already explained diffraction structure pattern, consisting of a holographic exposure 100 and a lattice structure generated by means of an electron beam 101 can also be produced by exposure of only one layer of photoresist. They show this case 11a to 11c , Before the exposure, the substrate is here 2 with a metal layer 70 a dark absorption layer 73 as well as a photoresist layer 71 applied. For holographic exposure of the background pattern 100 becomes this photoresist layer 71 with a mask 72 partially covered. In the 11a schematically shown mask 72 has, for example, the in 6 shown form. Not through the mask 72 covered area of the photoresist layer 71 is now, as in 11a represented by the superposition of two coherent light beams 75 . 76 exposed. The object beam 76 carries the information of the letter field 102 , this in 5 is shown. By superimposing the object beam 76 with the reference beam 75 arises in the photoresist layer 71 the holographic diffraction structure 77 in the form of the letter field 100 , like in 7 shown in the area 101 has a gap. This gap 101 is off the mask 72 covered and is therefore not yet exposed at this point in the process. Then the mask 72 removed and in this previously unexposed area of the photoresist layer with an electron beam 78 the lattice structure 79 enrolled. This process step shows 11b , The metal layer 70 ensures that the electrons of the electron beam are derived in this process step 78 , The dark absorption layer 73 on the other hand, during holographic exposure ensures that no disturbing light reflections occur. Is it in the procedural steps 11a and 11b used photoresist layer 71 around a positive resist, so the photoresist layer has 71 after developing the in 11c shown relief structure.

Is used for the process steps according to 11a and 11b if, on the other hand, a negative resist is used, it has the in 12 relief structure shown.

The 13 to 15 show different layer sequences on the substrate 2 disposed can be and in the in 11 described methods are usable. For example, the dark absorption layer 73 to be dispensed with if as a substrate layer 2 a dark colored glass is used. Instead of the metal layer 30 can also be a conductive polymer 80 be used ( 13 ). It is also possible to use the metal layer 70 to be used simultaneously as a drainage layer and as a mask. This case shows 14 , As a substrate 2 a dark colored glass can also be used here. According to another alternative ( 15 ) the mask 72 also be built up in multiple layers and made of a glass plate or plastic film 81 exist on which the masking metal layer 82 is applied in a separate process step. The structuring of the metal layer 82 can be done using known washing or etching processes. That mask 72 is on the photoresist layer 71 hung up. It can help between the mask 72 and the photoresist layer 71 arrange a layer of glycerin to avoid reflections on the surface of the photoresist layer. Instead of glycerin, a suitable other substance can be used which has approximately the same refractive index as the photoresist layer 71 and the glass layer 81 having.

An alternative method of making the resist master 110 according to 4 shows 16a to 16d , Here, the use of masks is dispensed with, so that the diffraction structures produced 100 . 101 overlap. That is, the diffraction structure forming the foreground 101 is above the letter field 100 arranged and replaced in this image area the letter field forming the background.

In 16a becomes one with a photoresist 1 coated substrate 2 with coherent radiation 195 so exposed that in the resist 1 a latent grid image 196 arises. Then the resist 1 developed. An intermediate product as in 16b shown. The grid picture 196 gives the letter field 100 again. A photoresist layer is now applied to this intermediate product 197 applied, which, due to its consistency and the greater layer thickness, spills and levels out the previously applied structure, such as 16c shows. With an electron beam 198 becomes a latent image 199 in the layer 197 generated, the exposure being such that the layer is not exposed through to the bottom. 16d shows the result after development. The diffraction structure 101 overlays and replaces the diffraction structure of the letter field 100 , In this way, a uniform diffraction structure can easily be provided with additional, preferably individualizing information.

17a to 17c show a further variant in which two different types of radiation are exposed in a photoresist layer, in this case the images produced by the exposures overlap. In 17a becomes one with photoresist 1 coated substrate 2 with radiation 3 (eg laser light) so exposed that a latent grid image in the photoresist 196 arises. After that, as in 17b shown with a different type of radiation 190 , such as electron radiation, again exposed so that the first grid image 196 another grid picture 191 superimposed. 17c shows the result of the procedure after the development of the photoresist layer 1 , The final grid structure 194 therefore consists of an overlay of the grid images 196 and 191 ,

At the in 17 The procedure shown is a photoresist 1 needed, which is equally suitable for both types of radiation, which is not feasible for all types of radiation. 18a to 18d show a method that can be used for all types of radiation. In 18a again with photoresist 1 coated substrate 2 with radiation 3 , such as laser light, so exposed in the photoresist 1 a latent grid image 196 arises. After that, the photoresist 1 developed. An intermediate product as in 18b shown. Another layer of photoresist is now applied to this intermediate product 192 applied that in layer thickness and sensitivity of exposure with the type of radiation 190 , for example electron radiation, is optimally adapted. As in 18c shown results from the exposure with the type of radiation 190 in the shift 192 the latent image 193. 18d shows the result after photoresist development. The final grid structure also exists here 194 from an overlay of the grid images 196 and 193 ,

Of course, any other layer structures can also be used for the method according to the invention. Under certain circumstances it may make sense to place the reflection-preventing absorption layer on the underside of the substrate 2 to be arranged so that the photoresist layer and absorption layer are arranged on different surfaces of the substrate.

Furthermore, substrates can be used in all of the methods shown are used that already have a diffraction structure are, e.g. Electroplated shims, embossed plastic or metal foils. In certain circumstances however, it is sufficient to use these special substrates with just one to provide further photoresist layer and this according to the illustrated Expose procedure.

All of the described process variants can be combined with one another as desired. According to the Resistmaster 4 The methods explained can also be used for the production or combination of other different grid images.

The relief structures or exposed substrates can be processed as resist masters in the usual way as in optical holography. In the following, a thin silver layer is therefore applied by vapor deposition or chemical precipitation wear and made a nickel impression in the electroplating bath. The nickel impression can be multiplied and used as an embossing tool for embossing an embossing layer. The embossing layer is finally transferred to the final substrate, for example a bank note, credit card or packaging material, with or without a metallic, shiny reflective layer.

Claims (38)

Process for the production of a resist master, which has at least two different image areas, wherein in the manufacture of the resist master at least two photoresist layers are used, depending on the type of image areas to be produced are adjusted. A method according to claim 1, characterized in that the photoresist layers in the image areas in different Layer thickness can be applied. A method according to claim 2, characterized in that the photoresist layers are made of the same material. Method according to at least one of claims 1 to 3, characterized in that the photoresist layers to the Type of the relief profile to be produced are adapted. Method according to at least one of claims 1 to 4, characterized in that the photoresist layers to different Radiation types are adjusted. Method according to at least one of claims 1 to 5, characterized in that the photoresist layers one above the other to be ordered. Method according to at least one of claims 1 to 6, characterized in that the different image areas at least partially overlay. A method according to claim 7, characterized in that the overlapping Image areas are exposed in a photoresist layer. A method according to claim 7, characterized in that the overlapping Image areas in one another lying photoresist layers are exposed. Method according to at least one of claims 1 to 7 with the following steps: - coating the substrate with a first photoresist, - loading the first Photoresists with radiation of a first radiation type in the first Image area, - Develop the first photoresist, - Apply a second photoresist layer on the substrate, - Apply of the second photoresist with radiation of a second radiation type in the second image area, - Develop of the second photoresist. Method according to at least one of claims 1 to 9 with the following steps: - coating the substrate with a first photoresist of first layer thickness, - Apply the first photoresist with radiation in the first image area, - Develop the first photoresist, - Apply a second photoresist layer of second layer thickness on the substrate, - Apply the second photoresist with radiation in the second image area, - Develop of the second photoresist. Method according to one of claims 1 to 11, characterized in that for the first photoresist layer ( 1 . 12 . 24 ) and for the second photoresist layer ( 9 . 19 . 32 ) a positive or a negative resist is selected in each case. Method according to one of claims 1 to 11, characterized in that for the first photoresist layer a negative resist ( 1 . 19 . 32 ) and a positive resist for the second photoresist layer ( 12 . 19 . 24 ) is used or vice versa. A method according to claim 12 or 13, characterized in that in the case of a positive resist ( 12 . 19 . 24 ) the associated image area is first exposed and then using a mask ( 15 . 22 ) the surrounding area with radiation ( 16 . 23 . 30 ) is applied. Method according to one of claims 1 to 14, characterized in that between the first photoresist layer ( 1 . 12 . 24 ) and the second photoresist layer ( 9 . 19 . 24 ) a barrier layer ( 31 ) is applied. A method according to claim 15, characterized in that for the barrier layer, a metal or oxide layer ( 31 ) is selected. Method according to one of claims 1 to 16, characterized in that for the radiation ( 3 . 10 . 13 . 20 . 33 ) particle radiation or electromagnetic radiation is selected from the first and second radiation types. A method according to claim 17, characterized in that for the radiation ( 3 . 10 . 13 . 20 . 33 ) an electron beam or laser is selected from the first or second radiation type. Method according to at least one of claims 1 to 18, characterized in that in the first and / or second photoresist layer Diffraction structures are exposed or written. Method according to at least one of claims 1 to 19, characterized in that in at least one of the image areas a real hologram is exposed. Method according to at least one of claims 1 to 20, characterized in that in at least one of the image areas a grid image is written or exposed. Method according to at least one of claims 1 to 21, characterized in that in at least one of the image areas a zero order grid image is written or exposed. Method according to at least one of claims 1 to 21, characterized in that generates more than two image areas become. Method according to at least one of claims 1 to 23, characterized in that at least one of the photoresist layers on a glass plate, an embossed one Plastic or metal foil or a galvanic shim applied and is exposed there. Process for producing a resist master, the has at least two different image areas, the Substrate is provided with a photoresist layer, and the photoresist layer in one image area with light radiation and in the other image area is exposed to particle radiation. A method according to claim 25, characterized in that the different image areas overlap at least partially. Process for producing a resist master, the has at least two different image areas, with on a substrate with a diffraction structure in the form of a relief structure is provided, a photoresist layer is applied, and the Photoresist layer is exposed in one of the image areas, and the unexposed areas of the photoresist layer are removed, so that the relief structure underneath is exposed and forms the second image area. A method according to claim 27, characterized in that a galvanic shim or an embossed plastic or metal foil is used. Resistmaster, produced by a process according to at least one of the claims 1 to 28. Resist master with at least one photoresist layer, which has a first image area which exposes to light radiation and a second image area that is exposed to particle radiation is. Resist master with at least two photoresist layers, wherein each photoresist layer exposes in at least one image area and the image areas in the two photoresist layers with different types of radiation are exposed. Resist master with at least one photoresist layer, which has a first image area, the first image area which is exposed with a zero order grating image, and a second image area with a first-order grid image is exposed. Resist master with at least two photoresist layers, wherein each photoresist layer exposes in at least one image area and the photoresist layers have different layer thicknesses exhibit. Resist master according to claim 33, characterized in that a zero-order grating image is exposed in each photoresist layer is. Resist master according to at least one of claims 30 to 34, characterized in that the image areas at least partially overlay. Security element made with a resist master according to at least one of the claims 29 to 35. Use of the resist master according to one of claims 29 to 36 for the production of embossing tools, especially embossing cylinders. A method of making a resist master, wherein an embossable lacquer layer on an already structured carrier material is applied, in which a grid image is embossed.